Gay and Lesbian theatre is a more modern form of theatre. There were a few shows with homosexuality in the late 1920s and early 1930s, but gay and lesbian theatre's popularity grew in the second half of the twentieth century due to a growth of off-broadway experimentation in the 1950s and the sexual revolution of the 1960s. These events caused homosexual playwrights, actors, and directors to consider their own difficulties in life. In 1975, an explosion of transvestite theatre was brought about from urban subculture. Gender-benders used shock tactics and reverse glamour to achieve their desired effects. Many theatres were founded in the 1970s and 1980s that were specifically dedicated to gay and lesbian theatre. Other groups with similar goals began to form in other cities, and the Gay Theatre Alliance was born. Its first festival was held in 1980. Feminist theatre groups inspired many lesbian plays that produced satiric revenue. The AIDS epidemic inspired many nonce dramas and modern versions of the problem play, where the message is more important than the medium itself.